Surprising? Aren't tequila and margaritas part of the all-American rite of raucous partying that makes so many Mexican restaurants look like college frat houses? Although they may not remember in the morning, Americans have been getting to know rotgut tequila for decades, through machine-churned frozen margaritas or the old lick-the-salt, knock-it-back, suck-the-lime method.

But the American relationship with tequila has been changing. While tequila sales in the United States have grown vigorously in the last few years, high-end and superpremium brands, the kind that you wouldn't want to drown with sweetened mango-and-nectarine syrup, have led the way by far. Sales in these categories have increased by more than 20 percent a year since 2002, according to the Distilled Spirits Council, a trade group. Yet despite tequila's popularity, Mr. Freeman is right. It remains little understood and sadly undervalued.

Simply put, tequila is one of the world's greatest spirits, thrillingly complex and thoroughly distinctive. Most cheap tequilas bear scant resemblance to tequila at it best. Like squares of American cheese that get the job done on a burger but cannot begin to suggest the majesty of a great Parmesan, cheap tequila serves its purpose when the primary goal is intoxication, but offers only a hint of tequila's real stature.

Along with Mr. Freeman, Florence Fabricant and I were joined for the tasting by Sue Torres, the chef and an owner of Sue? a Mexican restaurant in New York that emphasizes the richness of Mexican cuisine and the role of tequila in its enjoyment.

We had two requirements for the tequilas in our tasting. First, they had to be made from 100 percent blue agave. Tequila is made from the distilled sap of the blue agave, which is a succulent (but not a cactus). The best tequilas are 100 percent agave, while lesser mixto tequilas can squeak by with a minimum 51 percent agave. If the label does not say 100 percent agave, it is a mixto.

The second requirement was that they be reposados. Tequilas have three levels of aging. The youngest tequilas are called blanco, or sometimes plato or silver. They are essentially bottled without aging. The oldest are the a?s. They must be aged at least a year in oak barrels, though they generally spend three to five years in oak. In the middle are reposados, which rest in oak barrels from two to 12 months.

Personally, I have always liked blancos best. They offer an undiluted taste of what tequila is all about, with pronounced citrus, mineral and herbal aromas and flavors in varying proportions depending on whose tequila you're tasting. I love a good margarita, served straight up with salt, but frankly a great blanco tequila is almost like a margarita without the cocktail additions -- the salt and citrus flavors are built in. All it lacks is sweetness. I have nothing against a? tequilas, but it seems to me that barrel aging diminishes the qualities that make tequila singular. The rough edges are all smoothed out and the tequila sometimes takes on a caramel flavor, more like a Cognac or an aged rum. Yet many fans swear by the sipping virtues of a?s, and I do not doubt them. A?s are generally not for mixing into cocktails.

That leaves reposados, which are what? Somewhere in between, I guess. Reposados account for more than half of all tequila sales in Mexico, but in the United States they are something of an enigma.

For me, the tasting of 21 reposados went a long way toward answering my questions about what to do with them. First of all, reposados come in a range of styles and flavors, as our top three tequilas illustrate. Our No. 1 bottle, the El Tesoro de Don Felipe, seemed to display all of the explosiveness of a blanco tequila. It was full of citrus, herbal and saline flavors, yet it was exceptionally smooth at the same time.

The Herradura, our No. 2 bottle, was on the a? side of the reposado spectrum, mellow and also complex, but with other sorts of flavors like butter and caramel standing out. Positioned in the middle was the Chinaco, our No. 3 bottle, which had the briny, herbal, vegetal characteristics of a blanco but the easygoing balance of an a?.

Such a balancing act is not easy for a distiller, and we were all impressed by the high quality of almost all of the tequilas we tasted. On the blanco side among the top 10 were the Frida Kahlo, named for the great Mexican artist, and, at $65, the most expensive tequila in the tasting, and the Coraz?which at $34, was our best value. On the a? side were the Gran Centenario, the Don Julio and the Siembra Azul. And somewhere in the middle were the Casa Noble and the Cabo Wabo. Incidentally, the Cabo Wabo brand is owned by the singer Sammy Hagar, who follows in a tradition of entertainers associating themselves with fine tequila. The first were Bing Crosby and Phil Harris, who originally imported Herradura into the United States in the 1950's.